The present invention relates to fire barrier apparatus and method for closing off a penetration in a wall, floor, partition or ceiling to the passage of heat, smoke and toxic gases in the event of a fire.
A generally used method for passing electrical cables, conduits and other mechanical services through a barrier such as a fire resistant wall or floor is directly through a penetration or opening in the barrier. When such a penetration is not provided with a sealing means around the cable, etc., it will permit the direct passage of heat, smoke and toxic gases generated by a fire.
Various devices have been developed for sealing penetrations against the passage of heat, smoke and gases. McMartin, U.S. Pat. No. 3,864,883, relates to apparatus for closing a passageway in an under floor access housing and utilizes a shaped block of intumescent material which, in the event of fire, foams and expands to substantially fill the access housing. The shaped block of intumescent material is positioned in the housing and has dimensions less than the internal dimensions of the housing so that an opening remains around the body of intumescent material.
Another type of device exemplified by Bradley et al., U.S. Pat. No. 4,061,344, utilizes layers of intumescent material and elastomeric material sandwiched between metal compression plates. Cables, pipes or conductors are passed through holes bored in the plates, intumescent and elastomeric materials, and are held tightly enough to form a smoke seal by tightening the compression plates. An obvious disadvantage of this device is that it requires the cable, pipe or conductor diameter to match the hole diameter bored in the device components. In addition, the metal screws or bolts used to tighten or compress the plates together act as conductors of heat in a fire.